A pathological embedding cassette is used as a container for preparing and storing a pathological paraffin specimen in hospitals. A pathological embedding cassette needs to be immersed in an organic solution such as formaldehyde, ethanol, and xylene during the preparation of a pathological specimen. Therefore, a pathological embedding cassette is usually made of polyoxymethylene (POM) plastic to withstand immersion in the organic solution. In order to label a pathological specimen, a specially-made pencil may be used to handwrite characters on a POM pathological embedding cassette or a label strip is manually bonded on the POM pathological embedding cassette after a specimen preparation process is completed. Manual methods have very low efficiency and a high error rate. If a pathological embedding cassette printer is used to directly print characters or a barcode on a POM pathological embedding cassette, the working efficiency can be greatly improved and human errors can be reduced. An oil solvent-based inkjet technology is frequently used in the printing industry. Characters formed via jetting can be adsorbed on the surface of a POM pathological embedding cassette, but will fall off after immersion in an organic solution such as xylene. As a result, an application requirement cannot be achieved. Water-based ink cannot adhere to the surface of a POM pathological embedding cassette at all.
In order to print characters on a POM pathological embedding cassette and enable the printed characters to resist abrasion and withstand immersion in organic solutions, a method of an ultraviolet curable ink is used previously. That is, an ink jet cartridge filled with ultraviolet curable ink is used to print characters on a pathological embedding cassette, and an ultraviolet lamp is then used to irradiate the characters, so as to cure ultraviolet ink on a plastic surface of the embedding cassette, thereby achieving the objective of enabling the characters to resist abrasion and withstand immersion in organic solutions instead of easily falling off. A method of a thermal ribbon is also used. That is, one heatable array printing head is used. The printing head is heated and pressed on the thermal ribbon, to further thermally press thermal toner on the ribbon into the surface of the POM pathological embedding cassette. In this way, the printed characters can also resist wear and withstand immersion in organic solutions.
Recently there is also a method of using a laser beam with controllable deflection to irradiate the surface of a POM pathological embedding cassette coated with a special material. A portion with a coating layer is irradiated with the laser beam, and colors change under high temperature to form characters. The method of coating with a special material is to resolve a coloring problem after POM plastic is irradiated with laser. As shown in FIG. 1, under irradiation of high-energy laser, the surface of POM plastic without a special coating layer is only thermally melted and deformed, and the colors of irradiated portions have no significant change and cannot be easily recognized.
In addition, in existing structures, the position of a POM embedding cassette is not directly detected, and an indirect position calculation manner is used for ink ejection and laser beam irradiation on the surface of the POM embedding cassette. As a result, the quality of printing and curing is affected.